Well, according to the T-Pain song of the same name, "I'm sprung" means you're so in love with a woman, that you'd basically do anything for her. (Check out the slightly NSFW video.) As T-Pain sings in his beautifully robotic Auto-Tuned voice, the lady in his life has him "doing things I'd never do." These things include doing the dishes, cooking up a full breakfast of what looks like pancakes and eggs, and feeding her grapes. Basically, good boyfriend stuff. (Suspiciously, he also adds that she isn't his "main lady" and that he needs to get away from her. Oh, T-Pain. You scoundrel!) His friends in the video also do nice things for their ladies, such as grilling up burgers and shaving ice into homemade ice cream or posssibly icees for some reason. T-Pain declares his freedom from his lady, but love (and the fact that he's, uh, "horny") brings him back to his bewitching, grape-loving gal.

But then comes the twist-- all the lovey-dovey stuff has been a daydream that T-Pain is having at the strip club while watching a pole dancer. (After all, this is the guy who gave us the song "I'm In Love with a Stripper." Clearly, the guy has a type.) Turns out T-Pain is so head-over-heels with this dancer, he's thinking about treating her with respect instead of stuffing dollar bills into her sweaty g-string. According to Wikipedia, T-Pain dedicated "I'm Sprung" to his wife. Classy!

So "sprung" can be both metaphorical (he's so in love, he has a spring in his step) and also a description of what is happening in his general crotch region. Basically, he's got a hard-on for love.